Work in the coming year will build on achievements thus far attained in purifying microsomal glucuronyltransferase. We plan to finish this phase of the work within the next 8 months by utilizing isoelectric focusing and affinity chromatography of the partially purified enzyme. Once this is done, we will proceed to characterization of the structure of the p-nitrophenol metabolizing form of glucuronyltransferase, and separation of different substrate specific forms of this enzyme, and determination of the properties that confer specificity. We will continue, in addition, to study the direct membrane-to-membrane transfer of hydrophobic compounds, and the significance of this process for intracellular metabolism of drugs.